It would appear that the camera input on the board goes directly into
the Broadcom chip, but I haven't found any info on what happens to it
from there. My interest it to be able to use the camera input as a
generic high speed input, not necessarily for a camera like device. But
it is not at all clear what sort of software mods would be needed for that.
Is this at all feasible with this board?
Are you sure that access to the GPU is required?
First, do you know for a fact that the camera input goes directly to the
GPU and is not accessible by the CPU?
Second, what functions are already available through the GPU that could
be used? If the only function of the camera is to display the image
through the GPU, that would be a very unhelpful input. Surely the GPU
has a driver to allow the video to be sent to a file or piped or some
Not for definite, because the GPU-side memory map isn't documented and there
may be an address it can be poked somewhere that isn't mentioned. However,
there's quite a lot of postprocessing to be done:
I assume, but I haven't tried for sure, that it allows OpenMAX AL to get at
the camera functionality:
The XACameraItf looks like a reasonably comprehensive interface. See the
last page for examples of how to combine the interfaces (eg capture an image
then encode it).
However it's the GPU driver that's on the other end of that API.
The user-facing programs have most of the same functionality and use the
simpler mmal API:
Thanks for the links. They talk about being able to store the raw
"Bayer" data in the JPG meta data. There is even a thread from someone
else wanting to use the camera interface as a general purpose interface.